The development of efficient and stable electrocatalysts with earth-abundant elements for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in the same electrolyte is ...incontrovertibly vital in water electrolysis. However, their large-scale fabrication remains a great challenge. Here, we report a self-supported electrocatalyst in the form of Fe-doped Ni
3
S
2
nanoparticles
in-situ
grown on three-dimensional (3D) conductive Fe−Ni alloy foam (Fe−Ni
3
S
2
/AF) by surface-assisted chemical vapor transport (SACVT) method. Homogeneous growth environment and scalability of SACVT method allow Fe−Ni
3
S
2
nanoparticles uniformly growing on AF in large-scale. Fe−Ni
3
S
2
/AF exhibits high activity and durability when act as HER catalyst and OER precatalyst in alkaline media. The HER and OER overpotential at 10 mA/cm
2
is considerably small, only 75 and 267 mV, respectively. Moreover, the electrolyzer assembled by Fe−Ni
3
S
2
/AF for overall water splitting exhibits a low cell voltage and high durability in long-term test. Based on experiments and theoretical calculation, the significantly enhanced activity could be originated from the incorporation of Fe, which contributed to increase the electrochemical active surface area, enhance electrical conductivity, optimize the hydrogen and H
2
O adsorption energy of Ni
3
S
2
(101) surface in HER, and form active bimetallic Ni−Fe(oxy)hydroxide in OER. The excellent durability of self-supported Fe−Ni
3
S
2
/AF could be benefited from the
in-situ
growth of Fe−Ni
3
S
2
nanoparticles on 3D AF, which could ensure closely mechanical adhesion between active materials and substrate, promote charge transport and increase surface area. This work provides a facile method for large-scale synthesis of electrocatalysts with high activity and long-term durability for efficient water electrolysis in alkaline media.
Although Fe
3
O
4
particles have exhibited excellent microwave absorbing capacity and widely used in practical application due to the synergistic effect of magnetic loss and dielectric loss, their ...applications are still limited for the required high mass fraction in absorbers. To overcome this problem, the development of Fe
3
O
4
materials with low dimensional structures is necessary. In this study, the shape anisotropic Fe
3
O
4
nanotubes (NTs) with low mass ratios were applied to realize efficient microwave absorption. The NTs with different aspect ratios were prepared through facile electrospinning followed by two-step thermal treatments and mechanical shearing. The cross-linked nanotubular structure enabled the absorbers to have much higher electrical conductivity, multiple scattering, polarization relaxation and better anti-reflection surface, while the shape anisotropic NTs maintained significant multiple resonances with stronger coercivity. These all were beneficial to microwave absorption with enhanced dielectric loss, magnetic loss and sterling impedance matching. Results showed that the absorber with 33.3 wt.% of short Fe
3
O
4
NTs had minimum reflection loss of -58.36 dB at 17.32 GHz with a thickness of 1.27 mm, and had the maximum effective absorbing bandwidth (EAB) of 5.27 GHz when the thickness was 1.53 mm. The absorber with 14.3 wt.% of long Fe
3
O
4
NTs presented the widest EAB in certain radar band with attenuated 80.75% X band and 85% Ku band energy bellow -10 dB at the thickness of 2.65 and 1.53 mm, respectively. This study provided an approach for the development of shape anisotropic magnetic absorbing materials, and broadened their practical applications as magnetic absorbers.
► Recent applications of molecularly-imprinted polymers (MIPs) to sample preparation. ► We highlight new formats and microextraction methods for sample preparation. ► Trends in techniques with ...molecularly-imprinted polymers (MIPs) in sample preparation.
Molecularly-imprinted polymers (MIPs), possessing tailor-made recognition sites, can specifically rebind to a target molecule in preference to analogous compounds. Molecular-imprinting technology is a powerful tool in the development of highly selective analytical methods.
MIPs are especially good candidates as adsorbents for sample preparation, due to their high selectivity and their ability to pre-concentrate the analytes from a complex sample matrix.
In this article, we review and discuss the recent applications of MIPs to sample preparation. We briefly discuss the principle and the synthesis of MIPs.
We critically evaluate novel applications of MIPs in different formats, including solid-phase extraction, solid-phase microextraction, stir-bar sorptive extraction, and magnetic beads. We especially highlight new formats and microextraction methods. We then discuss the problems and the future expected trends in these research areas.
Traditional ionic liquids are sensitive to humidity but with long response time and nonlinear response. Pure liquid-state ionic liquids are usually hard for dehydration which have ultralong response ...time for humidity sensing. The immobilization of ionic liquids provide a possible way for high performance humidity sensing. Hydrophobic materials and structures also promised faster response in humidity sensing, because of easier desorption of water. In this work, we prepared flexible humidity sensitive composites based on hydrophobic ionic liquid and polymer. The combination of hydrophobic ionic liquid with hydrophobic polymer realized linear response, high sensitivity with low hysteresis to humidity. By adjusting the ratio of ionic liquid, not only the impedance but also the hydrophobicity of composite could be modulated, which had a significant influence on the humidity sensing performance. The morphology and microstructure of the material also affected its interaction with water molecules. Due to the diverse processing methods of polymer, highly transparent film fabricated by spinning-coating and nanofibrous membrane fabricated by electrospinning could be prepared and exhibited different response time, which could be used for different application scenarios. Especially, the fibrous membrane made with electrospinning method showed an ultrafast response and could distinguish up to 120 Hz humidity change, due to its fibrous structure with high specific surface area. The humidity sensors with ultrafast, linear response and high sensitivity showed potential applications in human respiratory monitoring and flexible non-contact switch. To better show the multifunction of ionic liquid-polymer composite, as a proof of concept, we fabricated an integrated humidity sensitive color change device by utilizing lower ionic liquid content composite for sensing in the humidity sensing module and higher ionic liquid content composite as the electrolyte in the electrochromic module.
This study aims to evaluate the effects of leader-member exchange (LMX) on job and life satisfaction among nurses in China and to examine the mediating effect of individual and collaborative job ...crafting between LMX and job and life satisfaction. The study recruited 263 nurses who worked in hospitals in Zhejiang province, China. A set of self-administered questionnaires were used to measure the variables of LMX, job crafting, job and life satisfaction. The data was analyzed using the partial least square structural equation modelling (PLS-SEM). The results reveal that LMX has a significant positive influence on job crafting and job satisfaction. Collaborative job crafting has a significant positive influence on the job satisfaction of nurses, whereas individual job crafting does not. Moreover, LMX will affect job satisfaction and life satisfaction through a partial mediating effect of both individual and collaborative job crafting. Finally, the article discusses the academically and practical implications, and also provide some suggestions and directions for the future research.
This research aims to clarify consumer purchase intentions (PIs) for organic food (OF) in China by investigating factors, including consumers’ food safety consciousness (FSC), health consciousness ...(HC), and attitude (AT) toward OF. To collect data for this study, online surveys were carried out sequentially among 350 respondents, and partial least squares structural equation modeling (PLS-SEM) was employed to test the proposed hypotheses regarding the direct and indirect effect of FSC on PI and the sequential mediating effect of HC and AT. The findings indicate that consumers’ FSC strongly influences their intention to purchase OF and is sequentially mediated by HC and AT. PI is also significantly impacted by HC and is mediated by AT, and AT directly significantly influences PI. Through multiple group analyses, the path from HC to AT is found to be moderated by education. Accordingly, suggestions for OF businesses and future research are provided to improve public health.
Due to the effect COVID-19 epidemic, promoting green consumption is now a key marketing strategy in the hospitality and tourism industry. As it is vital green hotels predict their customers' visit ...intention, this study attempts to discover the factors affecting Taiwan's Z-generation tourists' green hotel visit intention using an extended theory of planned behavior including personal moral norms (PMN) and environmental concern (EC). Data were gathered from 296 Z-generation tourists
an online survey, which was subsequently analyzed using partial least squares structural equation modeling. The results evidence that Z-generation tourists' attitude, subjective norms, (SN) and perceived behavioral control positively and significantly influence their green hotel visit intention, with attitude being the most significant factor. Moreover, the mediation model analysis indicates Z-generation tourists' attitude toward green hotels mediates the relationships between PMN, SN, EC, and visit intention. This study provides new insights into tourists' green hotel visit intention and emphasizes the importance of attitude in the formation of intention.
Molecularly imprinted polymer (MIP) is widely used in many fields because of its characteristics of high selectivity, chemical stability and easy preparation. To enhance the selectivity and ...applicability of solid-phase microextraction (SPME), a novel MIP-coated SPME fiber was firstly prepared by multiple co-polymerization method with tetracycline as template. It could be coupled directly to high-performance liquid chromatography (HPLC) and used for trace analysis of tetracyclines (TCs) in complicated samples. The characteristics and application of the fibers were investigated. The electron microscope provided a crosslinked and porous surface, and the average thickness of the MIP coating was 19.5
μm. Compared with the non-imprinted polymer (NIP) coated fibers, the special selectivity to tetracycline and structure-similar oxytetracycline, doxycycline, chlortetracycline were discovered with the MIP-coated fibers. The adsorption and desorption of TCs with the MIP-coated fiber could be achieved quickly. A method for the fluorimetric determination of four TCs by the MIP-coated SPME coupled with HPLC was developed. The optimized extraction conditions such as extraction solvent, desorption solvent, and stirring speed were studied. Linear ranges for the four TCs were 5.00–200
μg/L and detection limits were within the range of 1.0–2.3
μg/L. The method was applied to simultaneous multi-residue analysis of four TCs in the spiked chicken feed, chicken muscle, and milk samples with the satisfactory recoveries.
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•A synergistic effect between micelles and ultrasound on efficient matrix cleanup.•Turbidity for evaluating cleanup efficiency and chromatographic compatibility.•Good compatibility of ...cleanup with large-volume injection to enhance sensitivity.•A novel method for rapid analysis of polar drugs in blood and zebrafish samples.•A promising analytical tool for therapeutic drug monitoring and toxicology studies.
A novel ultrasound-assisted micellar cleanup strategy (UAMC) coupled with large volume injection (LVI) high performance liquid chromatography (HPLC) method was proposed and successfully applied to the analysis of cefathiamidine in complex biological samples such as whole blood, plasma, serum and even zebrafish, a challenging positive real sample. Based on the micelle-biomacromolecule interaction, the phase-separation feature of surfactant micelles and ultrasound cavitation, UAMC possessed an impressive matrix cleanup capability and could rapidly reach distribution equilibrium (approximately 2 min), which enabled simultaneous sample cleanup and analyte extraction within 8 min. Due to the high cleanup efficiency of UAMC, large volume of pretreated samples could be injected for analysis without peak broadening, impurity interference and column degradation. Thus, online analyte enrichment could be automatically performed to significantly improve method sensitivity by the column-switching LVI-HPLC system, a commercial HPLC system with small modifications. The UAMC-LVI-HPLC method creatively integrated sample cleanup, analyte extraction and on-column enrichment into simple operation. In addition, the UAMC-LVI-HPLC method enabled non-matrix-matched analysis of cefathiamidine in complex biological samples. This feature was helpful to address the problems caused by conventional matrix-matched or internal standard calibration methods, such as matrix bias, increased workload, limited availability of suitable blank matrices and the use of expensive internal standards. The method had low limits of detections (e.g., 0.0051 mg/L and 0.038 μg/g), wide linear ranges (0.030–100 mg/L and 0.15–489 μg/g), good linear correlation (R2 = 0.9999), satisfactory accuracy (97.6–109.7%) and excellent intra- and interday precision (0.5–4.9%). Thus, UAMC-LVI-HPLC is expected to be a promising candidate for bioanalysis in therapeutic drug monitoring or pharmacokinetic and toxicology studies in the future.
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